It's time to put a bottle of fuel injector cleaner in the gas tank when I fill up today, and I got to wondering about the directions:

"For best results, add entire bottle to nearly empty gas tank"

So in theory, if I fill up when my tank is half empty, do I need to add a bottle of this stuff for my next two fill ups?

What do you think? <img src="/images/graemlins/confused.gif" alt="" />